I have been advised that Apache is corrupt on my server and that I must reinstall it but I have absolutely no idea how to do this.

Can somebody please point me in the right direction?

if your run a control panel.. a easy way is to just reinstall your panel ( cpanel, ensim, plesk)


How to install apache:
http://httpd.apache.org/docs/install.html


or your can install a rpm from rpmfind.net